Priority-based admission control in a network with variable channel data rates

ABSTRACT

A method for priority-based admission control in a network, comprises receiving an admission request for transmitting an information flow to a network through a communication channel and determining an admissible region within a range of a channel data rate of a communication channel for an information flow in response to a priority of the information flow, where the priority of the information flow is one of a plurality of priorities of information flow. The admissible region is one of a plurality of admissible regions within the channel data rate range that correspond to different ones of the plurality of priorities of information flow, respectively, and each of the plurality of admissible regions within the channel data rate range is useable for transmitting information flow with a respective one of the plurality of priorities. Further included in the method is determining an available channel data rate of the communication channel for receiving the information flow by the network, and granting the admission request for the information flow after determining that the available channel data rate of the communication channel is within the admissible region of the channel data rate range.

BACKGROUND

In a communication or data network like a home network, through whichsmart devices, such as computers, televisions, appliances, etc., may beconnected through wireless and/or wired communication channels to acomputer, a television, etc., an admission request for transmitting aninformation flow to the network has been selectively granted to keep anoverall network load to a level below a maximum capacity of the network.As referred herein, smart devices that are connected to thecommunication network are communication stations (hereinafter,“stations” for short) that communicate with one another via thecommunication network.

If all things were equal for stations connected to a network, that is,the station had more or less the same transmission rates, informationflows with more or less same priorities, etc., network resources may befairly distributed among stations by granting an equal time of networkaccess to each station. However, stations connected to a network oftenhave communication channels with different transmission rates andinformation flows with different priorities. For instance, in a wirelesslocal area network (LAN), a data rate of a communication channel dependson varying channel conditions, such as path loss, shadowing, fading,etc. and on distances between stations and an access point.

Because of varying channel conditions and different distances betweenstations and an access point, especially in mobile stations, stationsconnected to a network through communication channels that have varyingchannel conditions and/or varying distances between the stations and anaccess point often vary their transmission rates to adapt to thechanging transmission conditions.

With respect to stations connected to a network with varyingtransmission rates as discussed above, one conventional way ofdetermining an admission request by a station for transmitting aninformation flow to a network has been to favor a granting of amaximization of an overall throughput of information flow in the networkby granting admission requests of stations with relatively hightransmission rates. However, the throughput maximization approach oftendiscriminates stations with relatively low transmission rates by denyingadmission requests from those stations, even when information flows fromsuch stations are of relatively high priorities in comparison to thepriorities of information flows from stations with relatively hightransmission rates.

Another method has been to use a required time fraction to ensure that asum of the required time fraction for a station's flow and required timefractions associated with other admitted information flows does notexceed a predetermined limit. This method may consider a cumulativedistribution function of channel data rate for a communication channelbetween each station and the network in estimating the required timefraction for a station to achieve a particular throughput and thereaftermaking an admissions control decision. However, this method does notgive a fair consideration to relative priorities of information flow.

Although there have been recent attempts to control admission requestsfor transmitting an information flow to a network with variable channeldata rates and prevent overloading the network, such attempts haveproven to be less than successful because the proposed solutions areinefficient in assigning network resources fairly among differentstations connected to the network.

SUMMARY OF THE INVENTION

Accordingly, in one example, there is provided a method forpriority-based admission control in a network that comprises receivingan admission request for transmitting an information flow to a networkthrough a communication channel and determining an admissible regionwithin a range of a channel data rate of the communication channel inresponse to a priority of the information flow, where the priority ofthe information flow is one of a plurality of priorities of informationflow. The admissible region is one of a plurality of admissible regionswithin the channel data rate range that correspond to different ones ofthe plurality of priorities of information flow, respectively, and eachof the plurality of admissible regions within the channel data raterange is useable for transmitting information flow with a respective oneof the plurality of priorities. Further included in the method isdetermining an available channel data rate of the communication channelfor receiving the information flow by the network, and granting theadmission request for the information flow after determining that theavailable channel data rate of the communication channel is within theadmissible region of the channel data rate range.

In another example, there is provided a system for priority-basedadmission control in a network. The system comprises an admissioncontroller configured to receive an admission request for transmittingan information flow to a network through a communication channel,determine an admissible region within a range of a channel data rate ofthe communication channel based on a priority of the information flowamong a plurality of priorities of information flow, and grant theadmission request for the information flow based on a determination thatan available channel data rate of the communication channel forreceiving the information flow by the network is within the admissibleregion of the channel data rate range. The admissible region is one of aplurality of admissible regions within the channel data rate range thatcorrespond to different ones of the plurality of priorities ofinformation flow, respectively, and each of the plurality of admissibleregions within the channel data rate range is useable for transmittinginformation flow with a respective one of the plurality of priorities.The system further includes a policy database configured to communicateto the admission controller information as to a priority of a userassociated with the information flow, where the admission controller isconfigured to use the information to determine the priority of theinformation flow.

In another example, there is provided a computer program productembodied on one or more computer readable mediums for priority-basedadmission control. The computer program product comprises instructionsto receive an admission request for transmitting an information flow toa network through a communication channel and obtain a priority of theinformation flow, where the priority of the information flow is one of aplurality of priorities of information flow. The computer programproduct further includes instructions for determining an admissibleregion within a range of a channel data rate of the communicationchannel in response to the priority of the information flow. Theadmissible region is one of a plurality of admissible regions within thechannel data rate range that correspond to different ones of theplurality of priorities of information flow, respectively, and each ofthe plurality of admissible regions within the channel data rate rangeis useable for transmitting information flow with a respective one ofthe plurality of priorities. Also included in the computer product areinstructions to determine an available channel data rate of thecommunication channel and grant the admission request for theinformation flow after determining that the available channel data rateof the communication channel is within the admissible region of thechannel data rate range.

BRIEF DESCRIPTION OF DRAWINGS

The embodiments of the invention will be described in detail in thefollowing description with reference to the following figures.

FIG. 1 illustrates a network resource manager in a priority-basedadmission control system according to an exemplary embodiment of theinvention;

FIG. 2 illustrates an assignment of conditional admissible regionswithin a channel data rate range of a communication channel to differentclasses of information flow, respectively, based on a cumulativedistribution function of a channel data rate of the communicationchannel according to an exemplary embodiment of the invention;

FIG. 3 illustrates an assignment of an admissible region within achannel data rate range of a communication channel, which is useable fortransmitting information flow with a particular priority class, based onan overall load on a network and a cumulative distribution function of achannel data rate of the communication channel according to an exemplaryembodiment of the invention;

FIG. 4 illustrates a flow-chart of a method for a priority-basedadmission control according to an exemplary embodiment of the invention;and

FIG. 5 illustrates a flow-chart of a method for a priority-basedadmission control according to another exemplary embodiment of theinvention.

DETAILED DESCRIPTION OF EMBODIMENTS

For simplicity and illustrative purposes, the principles of theembodiments are described by referring mainly to examples thereof. Inthe following description, numerous specific details are set forth inorder to provide a thorough understanding of the embodiments. It will beapparent, however, to one of ordinary skill in the art, that theembodiments may be practiced without limitation to these specificdetails. In some instances, well known methods and structures have notbeen described in detail so as not to unnecessarily obscure theembodiments.

A priority-based admission control for a network according to an examplegrants an admission request from a station connected to the network fortransmitting an information flow to the network through a communicationchannel. The admission request may be granted by the priority-basedadmission control based on a priority of the information flow and anoverall load on the network.

In another example, information flows from stations to a network may beclassified into a plurality of priorities based on a priority of a userassociated with the information flow and/or other quality of service(QoS) requirements. The plurality of priorities of information flow maybe determined based on any reasonably-suitable criteria useable forclassifying information flow according to priorities.

In determining whether to admit an information flow based on a priorityof the information flow, a cumulative distribution function of a channeldata rate of a communication channel for transmitting the informationflow may be first obtained to determine an admissible region within arange of a channel data rate of the communication channel, which isuseable for transmitting the information flow. The cumulativedistribution function may be obtained over a reasonably-suitable rangeof the channel data rate of the communication channel, such as a full orreasonably comprehensive range of the channel data rate of thecommunication channel.

In general, a cumulative distribution function of a channel data rate ofa communication channel represents a density function of probabilitythat an actual channel data rate of the communication channel is lessthan a channel data rate point on the channel data rate axis. Acumulative distribution function of a channel data rate of thecommunication channel may be determined by tracking the channel datarate of the communication channel throughout a reasonably-suitable rangeof the channel data rate of the communication channel, such as a full orreasonably-comprehensive channel data rate range of the communicationchannel.

As to a frequency of performing the tracking and determining of thechannel data rate for determining the cumulative distribution functionof the channel data rate on the communication channel, the channel datarate of the communication channel may be tracked and determined once forall admission requests for information flow on the communication channelor be updated, for instance, with each admission request for informationflow.

Using the cumulative distribution of the channel data rate of thecommunication channel, as determined above, different regions of thechannel data rate range correspond to different priorities ofinformation flow, respectively. With such assignment of differentregions of the channel data rate range to different priorities ofinformation flow, respectively, a probability of an admission to thenetwork for an information flow with a particular priority class isequal to a difference between a maximum point and a minimum point on thecumulative distribution axis of the cumulative distribution functionacross the region assigned to the priority of the information flow.

In assigning different regions of the channel data rate range based onthe cumulative distribution function of the channel data rate of thecommunication channel, the assignment may be made by anyreasonably-suitable way of matching a priority of information flow withan appropriate probability of an admission for information flow with thepriority. According to an example, an admissible region within a channeldata rate range of a communication channel, which is useable fortransmitting an information flow with a relatively higher priorityclass, may correspond to a higher probability of admission to thenetwork.

According to another example of assigning different regions of thechannel data rate range based on the cumulative distribution function ofthe channel data rate of the communication channel, the channel datarate range is first divided into a plurality of non-overlapping regions.After the division of the channel data rate range into the plurality ofnon-overlapping regions, the non-overlapping regions may be grouped intodifferent groups, which groups in turn correspond to differentpriorities of information flow, respectively. In assigning differentgroups of non-overlapping regions to different priorities of informationflow, respectively, a non-overlapping region having the lowest channeldata rate and being assignable for transmitting information flow on thecommunication channel may be dedicated to information flow with thehighest priority class.

The above-discussed assignment of different groups of non-overlappingregions of a channel data rate range of a communication channel todifferent priorities of information flow, respectively, may be designedto give a relatively higher probability of admission for informationflow with a relatively higher priority class than for information flowwith a relatively lower priority class. For instance, such a design maybe accomplished by assigning admissible regions such that they arenested in order of priorities, wherein the largest of the admissibleregions corresponds to the highest priority class.

In addition to using a priority of an information flow in determiningthe admissible region useable for transmitting the information flow, anoverall load on the network, to which an admission of the informationflow is requested, may also be taken into considerations in thedetermination. In using the overall load on the network in determiningthe admission request for the information flow, a conditional admissibleregion useable for transmitting the information flow may be firstdetermined based on the priority of the information flow and by assumingthe overall load on the network to be within a reference load rangeamong a plurality of increasingly higher ranges of the overall networkload.

After determining the conditional admissible region useable fortransmitting the information flow by assuming the overall network loadto be within the reference load range as discussed above, a size of theconditional admissible region useable for transmitting the informationflow may be successively increased or decreased with each successiveincrease or decrease of the range of an overall network load among theplurality of increasingly higher ranges of the overall network loadrelative to the reference load range.

An overall load on a network may be any reasonably-suitable overall loadon the network that may be competitively distributed among differentstations of the network, such as an access to a central processing unitin the network, an access to wireless access points, etc. The overallnetwork load may be measured by any reasonably-suitable method ofmeasuring a network load, such as a detection of a channel-busy period,average collision ratio, etc. The overall network load used in thedetermination of the admissible region within the channel data raterange may be a current overall load on the network. Alternatively, anyreasonably-suitable past and/or projected overall load on the networkmay be used with or in place of the current overall load on the network.

As to the above-described sequence of firstly determining a cumulativedistribution function of a channel data rate of a communication channel,secondly determining a conditional admissible region within a channeldata rate range of the communication channel, which is useable fortransmitting an information flow, and thirdly determining an admissibleregion within the channel data rate range, which is useable fortransmitting the information flow, it should be apparent to those ofordinary skill in the art that other steps may be added or existingsteps may be removed, modified or rearranged without departing from ascope of a priority-based admission control according to an example.

Turning now to FIG. 1, shown therein is a network resource managerwithin a priority-based admission control system 100 according to anexample. In describing operations of the priority-based admissioncontrol system 100 briefly, a station 110 connected to a network that ismanaged by a network resource manager 190 generates a session request torequest an admission of an information flow to the network. An admissioncontroller 130 determines whether to grant the admission request basedon a priority of the information flow and an overall load on thenetwork. It should be understood that the system 100 may includeadditional components and that some of the components described hereinmay be removed and/or modified without departing from a scope of thesystem 100.

Messages exchanged amongst different components of the network resourcemanager 190 and the station 110 are given in a table below.

Control Message Message Content Station Feedback Station ID, currentchannel data rate Session Request Station ID, user ID, interface ID, QoSrequirements Session Response Station ID, session request determination.Additional information if session request is accepted: flow ID, trafficparameters for QoS provisioning Channel Status Request Station IDChannel Status Response Station ID, current channel data rate,cumulative distribution function of channel data rate Policy RequestStation ID, flow ID, QoS requirements Policy Response User priority,traffic priority Admission Request Station ID, flow ID, user priority,QoS requirements Admission Response Station ID, flow ID, admissiondecision Resource Allocation Station ID, flow ID, traffic priority, QoSrequirements Transmission Station ID, flow ID, transmissionopportunities Opportunities

In describing the priority-based admission control system 100 in moredetail, the station 110 is connected to a network, which may compriseone or more other stations 110. The station 110 makes an admissionrequest for transmitting an information flow to the network through acommunication channel by communicating a session request message to aquality of service (QoS) manager 140. The session request messagecomprises an identification (ID) of the station 110, an identificationof a user associated with the information flow, an identification of aninterface, and QoS requirements for the information flow. The station110 receives a session response message from the QoS manager 140, whichcomprises an identification of the station 110 and a determination onthe session request. If the session request determination indicates thatthe session request is accepted, the session response message mayadditionally include an identification of the information flow andtraffic parameters for QoS provisioning.

The session response message received by the station 110 from the QoSmanager 140 indicates whether the session request has been accepted,which depends on whether the admission request for the information flowhas been granted by the priority-based admission control system 100.

The station 110 receives a transmission opportunities message for theinformation flow from a medium access controller 150 if a resourceallocation message is communicated from the QoS manager 140 to themedium access controller 150, indicating that the admission request foradmission for the information flow has been granted. The transmissionopportunities message from the medium access controller 150 comprisesinformation as to transmission opportunities for the station 110 intransmitting the information flow on the communication channel. Thetransmission opportunities message from the medium access controller 150further comprises an identification of the station 110 and anidentification of the information flow.

Further, the station 110 communicates a station feedback message to achannel monitor 120, which message comprises a current channel data rateof the communication channel. The station feedback message furthercomprises an identification of the station 110.

The channel monitor 120 receives the station feedback message from thestation 110. The channel monitor 120 also receives a channel statusrequest message from the admission controller 130, which messagecomprises an identification of the station 110. In response to thechannel status request message from the admission controller 130, thechannel monitor 120 communicates a channel status response message tothe admission controller 130, which message comprises the currentchannel data rate of the communication channel. The channel statusresponse message also comprises an identification of the station and acumulative distribution function of a channel data rate of thecommunication channel.

The admission controller 130 receives an admission request message fromthe QoS manager 140, which message comprises an identification of thestation 110, an identification of the information flow to be transmittedon the communication channel by the station 110, a priority of a userassociated with the information flow, and other QoS requirements for theinformation flow. The priority of a user and/or other QoS requirementsmay be used by the admission controller 130 to determine a priority forthe information flow. Further, the admission controller 130 receives achannel status response message from the channel monitor 120 andcommunicates an admission response message to the QoS manager. Theadmission response message comprises an identification of the station110, an identification of the information flow, and a determination onthe admission request.

In determining whether to grant the admission request for theinformation flow and communicating the determination to the QoS manager,the admission controller 130 determines an admissible region within achannel data rate range of the communication channel, which is useablefor transmitting the information flow, based on the priority of theinformation flow as described above. In determining the admissibleregion based on the priority of the information flow, the admissioncontroller 130 may use the cumulative distribution function of thechannel data rate of the communication channel.

Further, the admission controller 130 may use the priority of theinformation flow to determine a conditional admissible region within thechannel data rate range of the communication channel and determine theadmissible region useable for transmitting the information flow based onan overall load on the network. For instance, as described above, theconditional admissible region for the information flow, as determinedbased on the priority of the information flow, may be successivelyincreased or decreased with each successive increase or decrease of arange of the overall network load among a plurality of increasinglyhigher ranges of the overall network load relative to a reference loadrange. The admission controller 130 may determine overall network loadbased resources committed to existing information flows. Resourcescommitted to information flows may, for example, be represented by timefractions allocated to transmitting the information flows.

After determining the admissible region for transmitting the informationflow, a further determination is made as to whether a transmission timefor transmitting the information flow at a current channel data rate ofthe communication channel is within a maximum time slot allowed to thestation 110. If the time is within the maximum time slot allowed to thestation 110, an admission response message from the admission controller130 indicates a grant of the admission request for the information flow.Otherwise, the admission response message from the admission controller130 indicates a rejection of the admission request for the informationflow.

The admission controller 130 may be a single unitary device or multipledevices and any one or all of features of the admission controller 130may be distributed to the station and other components 120, and 140-160of the network resource manager 190. The admission controller 130 may beany reasonably suitable device that grants an admission request fortransmitting an information flow to a network through a communicationchannel based on a priority of the information flow. The admissiondetermination may additionally take into considerations an overall loadof the network.

Exemplary features of the admission controller 130 in addition to theabove-described exemplary features will be explained in detail inreference to priority-based admission control methods shown in FIGS.4-5.

While a current channel data rate of the communication channel has beenreferred to in describing the operations of the station 110, channelmonitor 120, and admission controller 130, any reasonably-suitable pastor projected channel data rate may be used alternatively to or inconjunction with the current channel data rate of the communicationchannel. Similarly, with respect to the overall network load used by theadmission controller 130 in determining the admissible region within thechannel data rate range, any reasonably-suitable past, current, orprojected overall load of the network, to which the admission of theinformation flow is requested, may be used alternatively or in anycombination.

The QoS manager 140 receives a session request message from the station110 and communicates a session response message to the station, asdescribed above. In response to receiving the session request messagefrom the station 110, the QoS manager 140 generates and communicates apolicy request message to a policy database 160, which message comprisesan identification of the station 110, an identification of theinformation flow, and QoS requirements for the information flow.

After the communication of the policy request message to the policydatabase 160, the QoS manager 140 receives a policy response messagefrom the policy database 160, which message comprises information as toa priority of a user associated with the information flow and a trafficpriority of the information flow. A priority of the user associated withthe information flow may be used to set a priority of the informationflow. A traffic priority may represent a priority for resourceallocation to an admitted information flow among different types oftraffic, such as voice, video, etc., and is used, for example, todetermine an allocation of buffering and transmission resources fortransmitting the information flow.

When the QoS manager 140 receives an admission response message from theadmission controller 130 that indicates a grant of the admission requestfor the information flow, the QoS manager 140 generates a resourceallocation message. The resource allocation message comprises theidentification of the station 110, an identification of the informationflow, a traffic priority of the information flow, and other QoSrequirements for the information flow.

The medium access controller 150 receives a resource allocation messagefrom the QoS manager 140 and communicates a transmission opportunitiesmessage to the station 110, as described above.

The policy database 160 receives a policy request message from andcommunicates a policy response message to the QoS manager 140 asdescribed above. The policy database 160 may be any reasonably suitabledatabase comprising any policy information associated with informationflow, such as priorities of users associated with information flow andtraffic priorities of information flow, etc.

Turning now to FIG. 2, shown therein is an assignment of conditionaladmissible regions within a channel data rate range of a communicationchannel to different priorities of information flow, respectively, basedon a cumulative distribution function 200 of the channel data rate ofthe communication channel according to an example. The cumulativedistribution function 200 starts from a value of zero and continues toincrease as the channel data rate of the communication channel increasesuntil the cumulative distribution function reaches a value of one whenthe channel data rate reaches a maximum channel data rate.

In assigning different conditional admissible regions of the channeldata rate range to different priorities of information flow,respectively, the channel data rate range is firstly divided into aplurality of non-overlapping regions C₁-C_(M) of the channel data raterange. Secondly, different groups of the non-overlapping regionsC₁-C_(M) correspond to different priorities of information flow,P₁-P_(M), respectively, as the conditional admissible regions useablefor transmitting information flow with the respective priorities. P₁ isthe highest priority class and P_(M) is the lowest priority class. Asshown with the conditional admissible region 211 useable fortransmitting information flow with the highest priority class P₁ in FIG.2, the conditional admissible region useable for transmitting aninformation flow with the highest priority class may extend across theentire channel data rate range of the communication channel and have thelargest width among a plurality of conditional admissible regionsassigned to different priorities of information flow, respectively.

Each successively lower priority class of information flow, P₂-P_(M),with respect to the highest priority class of information flow, P₁, hasa conditional admissible region, which upper boundary ends the maximumchannel data rate of the communication channel but lower boundary startsat a successively higher channel data rate respect to that of theconditional admissible region 211 for the highest priority class P₁ asshown in FIG. 2. Thus each successively lower priority class ofinformation flow, P₂-P_(M), with respect to the highest priority classof information flow, P₁, occupies a successively smaller conditionaladmissible region with respect to the conditional admissible region 211useable for transmitting information flow with the highest priorityclass P₁, as shown in FIG. 2.

Any other reasonably-suitable method of determining conditionaladmissible regions based on priorities of information flow may also beused. Each such method may give an information flow with a relativelyhigher priority class a higher probability of being admitted to thenetwork compared to an information flow with a relatively lower priorityclass.

The conditional admissible regions determined as described above may beadopted as admissible regions within the channel data rate range, whichare useable for transmitting information flows with differentpriorities, without any changes or may be rearranged, adjusted, and/orchanged based on other factors, such as an overall load on the network,to which the information flow is requested to be admitted.

FIG. 3 illustrates an assignment of an admissible region within achannel data rate range of a communication channel, which is useable fortransmitting an information flow with a priority P_(w), based on anoverall load on a network, and a cumulative distribution function 200 ofa channel data rate of a communication channel for transmitting theinformation flow according to an example. Firstly, a conditionaladmissible region 311 useable for transmitting the information flow witha priority P_(w), which is a collection of non-overlapping regionsC_(w)-C_(w+i) within the channel data rate range, is determined asdescribed above in reference to FIG. 2 by assuming that an overall loadon the network is in a reference load range among a plurality ofincreasingly higher ranges of the overall load on the network. In theexample of FIG. 3, the lowest overall network load range L₁ among aplurality of increasingly higher ranges of an overall load on thenetwork, L₁-L_(k), is the reference load range.

Secondly, an actual overall load on the network is determined. If theactual overall network load is in the lowest load range L₁, theconditional admissible region useable for transmitting an informationflow with the priority P_(w) is assigned as the admissible region fortransmitting information flow with the priority P_(w).

Otherwise, as a range of the overall network load successively increaseswithin the plurality of increasingly higher ranges of the overallnetwork load relative to the lowest overall network load range L₁, thelowest one of remaining non-overlapping regions C_(w)-C_(w+i) of theconditional admissible region are successively removed in determiningthe admissible region for transmitting an information flow with thepriority P_(w). Thus, as a range of the overall network loadsuccessively increases among the plurality of increasingly higher rangesof the overall network load relative to the lowest overall network loadrange L₁, the admissible region is successively reduced relative to theconditional admissible region determined for the information flow withthe priority P_(w).

FIG. 4 illustrates a flow-chart of a method 400 for a priority-basedadmission control according to an example. It should be apparent tothose of ordinary skill in the art that other steps may be added orexisting steps may be removed, modified or rearranged without departingfrom a scope of the method 400.

At step 401, an admission request for an information flow is received bythe network from a station, for instance, through the session requestfrom the station 110 to the QoS manager 140.

At step 402, a priority of the information flow is obtained, forinstance, by the admission controller 130 based on a priority of a userassociated with the information flow and/or other QoS requirements fromthe policy database 160.

At step 403, a load placed on a communication channel for transmittingthe information flow is obtained, for instance, by the admissioncontroller 130, based on QoS requirements for the information flow.

At step 404, a current channel data rate of a communication channel fortransmitting the information flow is obtained, for instance, from thestation 110 through the station feedback message conveyed to the channelmonitor 120, which in turn relays the current channel data rate of thecommunication channel to the admission controller 130 through thechannel status response message.

At step 405, a cumulative distribution function of a channel data rateof the communication channel is obtained, for instance, by the admissioncontroller 130 from the channel monitor 120 through the channel statusresponse.

At step 406, an overall load on a network connected to the station isobtained, for instance, by the admission controller 130, based on, forinstance, time fractions allocated to transmitting information flows.

At step 407, an admissible region within a channel data rate range ofthe communication channel, which is useable for transmitting theinformation flow, is determined based on the priority of informationflow and the overall network load.

At step 408, a determination is made as to whether the current channeldata rate of the communication channel is within the admissible regionof the channel data rate range.

If the current channel data rate is not within the admissible region ofthe channel data rate range, the admission request for the informationflow is rejected at step 411.

If the current channel data rate is within the admissible region of thechannel data rate range, a further determination is made at step 409 asto whether a transmission time for transmitting the information flow atthe current channel data rate of the communication channel is greaterthan a maximum time slot allowed for the station. The transmission timemay be determined, for instance, by dividing the load placed on thecommunication channel for transmitting of the information flow by thecurrent channel data rate.

If the transmission time is greater than the maximum time slot allowedfor the station, the admission request for the information flow isrejected at step 411.

If the transmission time is not greater than the maximum time slotallowed for the station, the request for the admission of theinformation flow is granted at step 410.

When the admission request for the information flow is rejected at step411, after a predetermined period of time, if the station 110 stilldesires to transmit the information flow to the network, at least oneadditional admission request may be made by the station 110 to start theadmission determination process of FIG. 4 all over again.

Turning now to FIG. 5, illustrated therein is a flow-chart of a method500 for a priority-based admission control according to another example.It should be apparent to those of ordinary skill in the art that othersteps may be added or existing steps may be removed, modified orrearranged without departing from a scope of the method 500.

At step 501, conditional admissible regions within a channel data raterange of the communication channel, which are useable for transmittingdifferent priorities of information flow, are determined, for instance,by the admission controller 130 based on a cumulative distributionfunction of a channel data rate of the communication channel.

At step 502, an admission request for an information flow is received,for instance, through the session request from the station 110 to theQoS manager 140.

At step 503, a priority of the information flow is obtained, forinstance, from the policy database 160.

At step 504, an overall load on a network connected to the station isobtained, for instance, by the admission controller 130, based on, forinstance, time fractions allocated to transmitting information flows.

At step 505, an admissible region within the channel data rate range,which is useable for transmitting the information flow, is determinedbased on the priority of the information flow and the overall networkload.

At step 506, a current channel data rate of the communication channel isobtained, for instance, by the admission controller 130.

At step 507, a determination is made as to whether the current channeldata rate of the communication channel is within the admissible regionof the channel data rate range.

If the current channel data rate is not within the admissible region,the admission request for the information flow is rejected at step 511.

If the current channel data rate is within the admissible region, a loadplaced on the communication channel for transmitting the informationflow is obtained at step 508, for instance, by the admission controller130, based on QoS requirements for the information flow.

At step 509, a determination is made as to whether a transmission timefor transmitting the information flow at the current channel data rateof the communication channel is greater than a maximum time slot allowedfor the station.

If the transmission time is greater than the maximum time slot allowedfor the station, the admission request for the information flow isrejected at step 511.

If the transmission time is not greater than the maximum time slotallowed for the station, the request for the admission of theinformation flow is granted at step 510.

When the admission request for the information flow is rejected at step511, after a predetermined period of time, if the station 110 stilldesires to transmit the information flow to the network, at least oneadditional admission request may be made by the station 110 to start theadmission determination process of FIG. 5 all over again.

The above described operations of a priority-based admission control inreference to exemplary features and embodiments of FIGS. 1-5 may becontained as a computer program product embodied on one or more computerreadable mediums. The computer program product may exist in a variety offorms both active and inactive. For example, the computer programproduct may exist as software program(s) comprised of programinstructions in source code, object code, executable code or otherformats whether compressed or uncompressed.

Exemplary computer readable mediums include conventional computer systemRAM, ROM, EPROM, EEPROM, and magnetic or optical disks or tapes.Concrete examples of the foregoing include distribution of the programson a CD ROM or via Internet download. In a sense, the Internet itself,as an abstract entity, is a computer readable medium. The same is trueof computer networks in general.

A priority-based admission control according to above-describedexemplary features and embodiments of FIGS. 1-5 grants a request for anadmission to a network for an information flow by first determining anadmissible region within a channel data rate range of communicationchannel, which is useable for transmitting the information flow, basedon a priority of the information flow. If a channel data rate of thecommunication channel is within the determined admissible region and atransmission time for transmitting the information flow on thecommunication channel is within a maximum time slot allowed to thestation, the admission request is granted. In determining the admissibleregion for the information flow, an overall load on a network may beconsidered.

A priority-based admission control according to exemplary features andembodiments of FIGS. 1-5 may be applied in any suitable communicationnetwork where a channel data rate of a communication channel of astation varies, such as a wireless channel or wired channel with varyingchannel conditions in a small or large network. One example of such anetwork is a small home network, where stations may be connected to abackbone network of a home network via a wireless channel and may varytheir transmission rates to adapt to mobility and a dynamic propagationenvironment.

Another example of a network having a station with varying transmissionrates is a wireless mesh network, where different networks may havedifferent transmission rates. In any such network with varyingtransmission rates of stations on the network, a priority-basedadmission control according to exemplary features and embodiments ofFIGS. 1-5 may be used to improve an admission control in the network.

While exemplary features and embodiments of FIGS. 1-5 have beenexplained within the context of each feature and embodiment, any one orall of the exemplary features and embodiments of the invention may beapplied and is incorporated in any and all of the embodiments of theinvention unless clearly contradictory.

While the embodiments have been described with reference to examples,those skilled in the art will be able to make various modifications tothe described embodiments without departing from the scope of theclaimed embodiments.

1. A method for priority-based admission control in a network, themethod comprising: receiving an admission request for transmitting aninformation flow to a network through a communication channel having achannel data rate range; obtaining a priority of the information flow,wherein the priority of the information flow is one of a plurality ofpriorities of information flow; dividing up the channel data rate rangeinto a plurality of non-overlapping regions; determining an admissibleregion within a range of a channel data rate of the communicationchannel in response to the priority of the information flow, wherein theadmissible region is one of a plurality of admissible regions within thechannel data rate range that correspond to different ones of theplurality of priorities of information flow, respectively, and each ofthe plurality of admissible regions is useable for transmittinginformation flow with a respective one of the plurality of priorities;determining an available channel data rate of the communication channelfor receiving the information flow by the network; and granting theadmission request for the information flow after determining that theavailable channel data rate of the communication channel is within theadmissible region of the channel data rate range, wherein determining anadmissible region within the channel data rate range comprises selectinga group of the non-overlapping regions as the admissible region.
 2. Themethod of claim 1, further comprising obtaining an overall load on thenetwork, wherein determining an admissible region within the channeldata rate range includes determining the admissible region in responseto the overall network load.
 3. The method of claim 2, whereindetermining the admissible region within the channel data rate range inresponse to the overall network load comprises: determining aconditional admissible region within the channel data rate range inresponse to the priority of the information flow, wherein theconditional admissible region is one of a plurality of conditionaladmissible regions within the channel data rate range that correspond todifferent ones of the plurality of priorities of information flow,respectively, by assuming that the overall network load is in areference load range among a plurality of increasingly higher ranges ofthe overall network load, each of the plurality of conditionaladmissible regions being useable for transmitting information flow witha respective one of the plurality of priorities; and determining theadmissible region within the channel data rate range by successivelyincreasing or decreasing a size of the conditional admissible regionwith each successive increase or decrease of a range of the overallnetwork load among the plurality of increasingly higher ranges of theoverall network load relative to the reference load range.
 4. The methodof claim 1, wherein one of the plurality of non-overlapping regionscorresponding to the lowest channel data rate within the channel datarate range and assignable for transmitting information flow is dedicatedfor transmitting information flow with the highest priority class amongthe plurality of priorities of information flow.
 5. The method of claim1, further comprising rejecting the admission request after determiningthat a transmission time for transmitting the information flow at thechannel data rate of the communication channel is greater than a maximumtime slot allowed for a station having the communication channel.
 6. Themethod of claim 1, further comprising obtaining a cumulativedistribution function of a channel data rate of the communicationchannel, wherein determining an admissible region within the channeldata rate range comprises using the cumulative distribution function inassigning the plurality of admissible regions within the channel datarate range to different ones of the plurality of priorities ofinformation flow, respectively.
 7. A system for priority-based admissioncontrol in a network, the system comprising: an admission controllerconfigured to receive an admission request for transmitting aninformation flow to a network through a communication channel having achannel data rate range, divide up the channel data rate range into aplurality of non-overlapping regions, determine an admissible regionwithin a range of a channel data rate of the communication channel basedon a priority of the information flow among a plurality of priorities ofinformation flow, and grant the admission request for the informationflow based on a determination that an available channel data rate of thecommunication channel for receiving the information flow by the networkis within the admissible region of the channel data rate range, whereinthe admissible region is one of a plurality of admissible regions withinthe channel data rate range that correspond to different ones of theplurality of priorities of information flow, respectively, and each ofthe plurality of admissible regions within the channel data rate rangeis useable for transmitting information flow with a respective one ofthe plurality of priorities; and a policy database configured tocommunicate to the admission controller information as to a priority ofa user associated with the information flow, wherein the admissioncontroller is configured to use the information to determine thepriority of the information flow, wherein the admission controllerdetermines an admissible region within the channel data rate rangecomprises selecting a group of the non-overlapping regions as theadmissible region.
 8. The system of claim 7, wherein the admissioncontroller is further configured to determine the admissible regionwithin the channel data rate range based on an overall load on thenetwork.
 9. The system of claim 7, wherein the assignment of theplurality of admissible regions within the channel data rate range todifferent ones of the plurality of priorities of information flow,respectively, is based on a cumulative distribution function of achannel data rate of the communication channel.
 10. A tangiblenon-transitory computer readable medium containing a program product forpriority-based admission control, the computer program productcomprising instructions to: receive an admission request fortransmitting an information flow to a network through a communicationchannel having a channel data rate range; obtain a priority of theinformation flow, wherein the priority of the information flow is one ofa plurality of priorities of information flow; divide up the channeldata rate range into a plurality of non-overlapping regions; determinean admissible region within a range of a channel data rate of thecommunication channel in response to the priority of the informationflow, wherein the admissible region is one of a plurality of admissibleregions within the channel data rate range that correspond to differentones of the plurality of priorities of information flow, respectively,and each of the plurality of admissible regions within the channel datarate range is useable for transmitting information flow with arespective one of the plurality of priorities; determine an availablechannel data rate of the communication channel for receiving theinformation flow by the network; and grant the admission request for theinformation flow after determining that the available channel data rateof the communication channel is within the admissible region of thechannel data rate range, wherein the instruction to determine anadmissible region within the channel data rate range comprises selectinga group of the non-overlapping regions as the admissible region.
 11. Thecomputer readable medium of claim 10, further comprising instruction to:obtain an overall load on the network, wherein determining an admissibleregion within the channel data rate range includes determining theadmissible region in response to the overall network load.
 12. Thecomputer readable medium of claim 11, wherein determining the admissibleregion within the channel data rate range in response to the overallnetwork load comprises: determining a conditional admissible regionwithin the channel data rate range in response to the priority of theinformation flow, wherein the conditional admissible region is one of aplurality of conditional admissible regions within the channel data raterange that correspond to different ones of the plurality of prioritiesof information flow, respectively, by assuming that the overall networkload is in a reference load range among a plurality of increasinglyhigher ranges of the overall network load, each of the plurality ofconditional admissible regions being useable for transmittinginformation flow with a respective one of the plurality of priorities;and determining the admissible region for the information flow bysuccessively increasing or decreasing a size of the conditionaladmissible region with each successive increase or decrease of a rangeof the overall network load among the plurality of increasingly higherranges of the overall network load relative to the reference load range.13. The computer readable medium of claim 12, wherein one of theplurality of non-overlapping regions corresponding to the lowest channeldata rate within the channel data rate range and assignable fortransmitting information flow is dedicated for transmitting informationflow with the highest priority class among the plurality of prioritiesof information flow.